This is a study of hydroxyurea and BCNU treatment of patients with anaplastic glioma, which ordinarily has a very bad prognosis. The hope is that hydroxyurea will inhiit the development of resistance to BCNU and will be toxic to tumor cells as well. Dosage of hydroxyurea is escalated in a somewhat complicated way. The purposes are to determine the maximal tolerated dose of hydroxyurea in brain tumor patients receiving IV BCNU and GCSF to estimate response rate in patients receiving hydroxyurea and BCNU, and to determine the efficacy of GCSF in treating neutropenia induced by combined BCNU and hydroxyurea.